The production of fuel components from renewable sources is of increasing interest in view of greenhouse gas production when using conventional fuel, i.e. fossil fuel or a mixture of fossil fuel components and renewable fuel components other than the ketone. Therefore, various methods for upgrading renewable material so as to be suitable for use in fuel have been studied in the art. Many of these methods employ large amounts of hydrogen gas in order to convert the oxygen-containing renewable material into hydrocarbon compositions suitable for fuel applications. However, since hydrogen gas is mainly produced from fossil sources, there still is desire for improvement regarding methods employing less hydrogen gas while yet providing high quality fuel components.
5-nonanone can be produced from various renewable sources. For example, the most common way of producing 5-nonanone from levulinic acid (LA) is the conversion of LA to γ-valerolactone (GVL), subsequent conversion of GVL to pentanoic acid (PA), which is then converted to 5-nonanone.
5-nonanone shows several advantages as an intermediate in the production of fuel components. 5-nonanone spontaneously separates from water so that no expensive separation process needs to be employed. Furthermore, 5-nonanone can be produced from pentanoic acid via ketonisation, which method does not require the addition of hydrogen but nevertheless significantly reduces the oxygen content of the bio-derived material. In the ketonisation reaction, the oxygen is removed in the form of carbon dioxide and water. However, the prior art still faces problems regarding selectivity and conversion rate in the production of 5-nonanone. Accordingly, processes for producing 5-nonanone from renewable sources in industrial scale and high selectivity and conversion rate are highly desired.
Prior art relating to the production of 5-nonanone and the production of fuel components and other chemicals via 5-nonanone is known in the art.
It is known that 5-nonanone can be produced from LA via GVL and pentanoic acid. The pentanoic acid can then be converted to 5-nonanone over Pd/Nb2O5. Unreacted pentanoic acid is the major impurity in the product 5-nonanone i.e. dibutylketone (DBK). The boiling points of 5-nonanone and pentanoic acid are very similar, so that separation of these two compounds using simple distillation methods is difficult. A series of flash separation and distillation as well as optional extraction using methanol may be used to obtain a purity of 90% or more. However, this technique requires large scale distillation and consumes much energy. Accordingly, there is still need for methods to produce 5-nonanone using a simplified and less energy consuming method.
Ketonisation of pentanoic acid to 5-nonanone, followed by hydrogenation to provide nonanol and optional oligomerization of an alkene such as non-4-ene derived from nonanol to produce hydrocarbon compositions is also known.
WO 2010/151343 A1 discloses ketonisation of pentanoic acid to 5-nonanone and use of 5-nonanone as a precursor for fuel applications.